The Retroviral Nucleocapsid (NC) Symposium (IRNCS) has historically focused on the biological role of the NC protein in HIV-1 and other retroviruses. Approximately 100-120 researchers worldwide have typically participated at this biennial symposium in an effort to generate a complete picture of the role of NC in retroviral pathogenesis. NC plays critical roles in (1) remodeling host and viral nucleic acids as a chaperone protein, (2) assembly and targeting the retroviral genomic RNA to new virus particles, and (3) protecting viral DNA and facilitating integration into host DNA. Some of these functions are performed by NC as part of the precursor Gag protein, and others are carried out by mature NCp7. More recent work shows that NC plays roles immediately following infection and in 2012, a role in retroviral restriction was discovered. NC therefore represents a suitable target for therapy. The symposium will provide a venue for researchers (principal investigators, postdoctoral fellows, students, research staff and representatives from biotechnology) to make progress in efforts to combat HIV-1/AIDS, as well as other retroviral diseases including cancer, by focusing on this central player in the viral lifecycle. The Retroviral NC Symposium has a long-standing record of research excellence, of promoting research collaborations, supporting young scientists, and including women and other individuals who have been traditionally underrepresented in science. This year, we will also emphasize the role of NC/Gag in assembly as the Retrovirus Assembly Meeting, held every 4 years since 2000 in Prague, will no longer be held. We are therefore renaming the conference as the 9th International Retroviral NC and Assembly Symposium (IRNCAS).